JP2005338467A - Optical branching device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical branching device which is high in wavelength uniformity of insertion loss and also low in polarization dependence loss. <P>SOLUTION: The optical branching device1 has on a substrate 10; a light incident part 21 on which light is made incident; optical branching parts 22A to 22G which branch the light made incident on the light incident part by prescribed ratios; light emitting parts 23A to 23H which guide the light branched by the optical branching parts to prescribed positions; and dummy patterns 24A to 24H which are made of the same material as for the light incident part, the optical branching parts and the light emitting parts and which are arranged on an area on the substrate independent of an area where the light incident part 21, the optical branching parts and the light emitting parts are provided so that the occupancy ratio which shows ratio between an area of the substrate from which the area where the light incident part, the optical branching parts and the light emitting parts are provided is eliminated and the area of the substrate becomes larger than 70%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical branching unit that can be used in the field of optical communication and the like, and outputs light input to an input end to a plurality of output ends.

As an optical waveguide circuit component, a PLC (Planer Light Wave Circuit) component is known. As an example of this PLC component, an example in which an optical waveguide circuit pattern is formed on a silicon substrate and a partially independent core pattern is provided on the substrate on which the optical waveguide circuit is formed has been reported (for example, Patent Document 1).
JP-A-11-271545

  However, in the proposal disclosed in Patent Document 1, the number of waveguides on the light incident side (area) and the number of waveguides on the light output side (area) are structural problems peculiar to the optical branching device that is a PLC component. For example, in dry etching, the etching rate is known to vary greatly on the substrate due to the loading effect. As a result, since the line width of the bent waveguide on the incident side after etching is formed narrower than the design value, the loss of the bent waveguide increases on the longer wavelength side of the used wavelength. As a result, there is a problem that the uniformity in wavelength of the insertion loss of the optical branching device deteriorates.

  In addition, after the etching, by providing a clad layer over the entire substrate including the core portion formed by etching, the clad layer becomes convex in the core portion, so that when the lid glass is fixed with an adhesive, There is a problem that PDL (Polarization Dependent Loss) deteriorates due to concentration of stress.

  An object of the present invention is to provide an optical branching device with high wavelength uniformity of insertion loss and low polarization dependent loss.

  The present invention is directed to a light incident portion where light is incident, a light branching portion that branches light incident on the light incident portion at a predetermined ratio, and guides the light branched by the light branching portion to a predetermined position. Holds the light emitting part, the light incident part, the light branching part and the adhesive layer formed on the light emitting part with a predetermined thickness, and the light incident part, the light branching part and the light emitting part. A substrate, a cover member that covers each of the light incident portion, the light branching portion, and the light emitting portion on the substrate via the adhesive layer; and the light incident portion, the light branching portion on the substrate. And the stress generated when the adhesive layer is cured is provided independently of the region where the light emitting portion is provided, and the light incident portion, the light branching portion, and the light emitting portion on the substrate, Or a stress equalizing member that suppresses acting on the entire region. There is provided an optical splitter to.

  That is, according to the optical branching device described above, the influence of stress generated when the cover member is fixed by the adhesive is reduced. Therefore, deterioration of the polarization dependent loss (PDL) after the cover member is bonded can be suppressed.

  Further, the present invention provides a light incident portion on which light is incident, a light branching portion that branches light incident on the light incident portion at a predetermined ratio, and light branched by the light branching portion on the substrate. Independently of the light emitting part that guides the position and the light incident part, the light branching part, and the light emitting part on the substrate, the same material as the light incident part, the light branching part, and the light emitting part is provided on the substrate. A stress leveling member provided on the substrate so that an occupation ratio indicating a ratio of a region excluding a region where the light incident portion, the light branching portion, and the light emitting portion are provided is greater than 70%. An optical branching device is provided.

  In other words, according to the optical branching device described above, when etching the regions used for the light incident part, the light branching part, and the light emitting part, the etching rate over the entire area of the substrate is made substantially uniform. As a result, the loading effect suppresses a difference in the thickness (width) of the regions used for the light incident portion, the light branching portion, and the light emitting portion, and the width (thickness) of each region is made uniform. The Accordingly, in the bent waveguide of the optical branching unit, excess loss on the long wavelength side can be reduced, and the wavelength uniformity of insertion loss is improved.

  Further, according to the present invention, a light transmission material layer having a refractive index higher than that of a substrate that can be used as an optical waveguide is deposited on the substrate to a predetermined thickness, and an optical signal is transmitted to the light transmission material layer. A second region for making the etching rate at the time of etching the first region substantially constant over the entire region with a predetermined interval around the first region used for the first region A region is defined, a non-etched pattern is formed in each of the first region and the second region, and the remaining region on the substrate is patterned by etching, and the light transmission material layer and the substrate remaining by the patterning are exposed. A third region different from the first and second regions is formed over the entire region by providing a material having a refractive index lower than that of the light transmission material layer to a predetermined thickness, and forming a third region in the third region. The cover member is bonded through an adhesive It is a manufacturing method of an optical branching device for.

  That is, according to the method for manufacturing an optical branching device described above, the influence of stress generated when the cover member is fixed with an adhesive is reduced. Therefore, deterioration of the polarization dependent loss (PDL) after the cover member is bonded can be suppressed. From the above, the yield is increased and the cost of the optical branching device is reduced.

  The present invention also provides a light incident portion where light is incident, a light branching portion that branches light incident on the light incident portion at a predetermined ratio, and the light branched by the light branching portion at a predetermined position. A light emitting part for guiding; an adhesive layer formed on the light incident part, the light branching part and the light emitting part with a predetermined thickness; the light incident part, the light branching part and the light emitting part; A substrate to be held; and provided on the substrate independently of a region where the light incident portion, the light branching portion, and the light emitting portion are provided, and the light incident portion, the light branching portion, and the When forming the light emitting portion, the line width, which is the length along the surface direction of each of the light incident portion, the light branching portion, and the light emitting portion on the substrate, becomes non-uniform. And a non-optical signal transmission region for reducing an optical splitter. That.

  In other words, according to the optical branching device described above, when etching the regions used for the light incident part, the light branching part, and the light emitting part, the etching rate over the entire area of the substrate is made substantially uniform. As a result, the loading effect suppresses a difference in the thickness (width) of the regions used for the light incident portion, the light branching portion, and the light emitting portion, and the width (thickness) of each region is made uniform. The Accordingly, in the bent waveguide of the optical branching unit, excess loss on the long wavelength side can be reduced, and the wavelength uniformity of insertion loss is improved.

  Further, according to the present invention, a light transmission material layer having a refractive index higher than that of a substrate that can be used as an optical waveguide is deposited on the substrate to a predetermined thickness, and an optical signal is transmitted to the light transmission material layer. A second region for making the etching rate at the time of etching the first region substantially constant over the entire region with a predetermined interval around the first region used for the first region A region is defined, a non-etched pattern is formed in each of the first region and the second region, and the remaining region on the substrate is patterned by etching, and the light transmission material layer and the substrate remaining by the patterning are exposed. A third region different from the first and second regions is formed by providing a predetermined thickness of a material having a refractive index lower than that of the light transmission material layer over the entire region. It is a manufacturing method of a turnout.

  That is, according to the optical branching device manufacturing method described above, when etching a pattern used for transmitting an optical signal, the etching rate varies depending on the position on the substrate due to the loading effect, and the incident side after etching It is prevented that the line width of the bent waveguide becomes narrower than the design value. Thereby, the loss of the bent waveguide is made uniform regardless of the wavelength used, and the optical characteristics are improved.

  According to the present invention, it is possible to form an optical branching device having high insertion loss wavelength uniformity and low polarization-dependent loss even after the cover member is bonded.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of an optical branching device to which an embodiment of the present invention is applied.

As shown in FIG. 1, the optical splitter 1 is, for example a substrate 10 mainly composed of silicon dioxide (Si0 ₂₎ or the like, an optical waveguide structure 20 formed by patterning in a predetermined shape on the substrate 10, the Have. The periphery of the optical waveguide structure 20 is covered with a clad member 30 for making the optical waveguide structure 20 usable as a core. The relative refractive index difference between the core portion and the clad portion is 0.45%.

  The optical waveguide structure 20 is incident on an incident end 21 where light (optical signal) supplied via an optical transmission member (not shown) such as an optical fiber or an optical splitter in the previous stage is incident. Optical branching units 22A to 22G that branch the optical signal at the first and second ratios, and the optical signal branched by the optical branching units 22A to 22G (in this example, 8) are connected to a subsequent stage (not shown), for example, It includes output ends 23A to 23H for guiding to a single mode fiber or a subsequent optical branching unit.

  In the periphery of the optical waveguide structure 20 and in the region where the clad member 30 is deposited, the same material as that used as the core portion deposited on the substrate 10 in the same process as the optical waveguide structure 20 is provided. When patterning the core portion (optical waveguide structure) 20, stress equalizing members (hereinafter referred to as dummy patterns) 24A to 24H left in a predetermined shape are provided. That is, the dummy patterns 24 </ b> A to 24 </ b> H are regions that remain without being etched when the optical waveguide structure 20 deposited on the substrate 10 is etched by, for example, dry etching to form the core portion 20.

The optical waveguide structure (core portion) 20 and the dummy patterns 24A to 24H are formed, for example, by patterning a glass layer mainly composed of silicon dioxide formed on the substrate 10 to a predetermined thickness into a predetermined shape. The optical waveguide structure 20 may be formed by, for example, depositing a clad layer member (not shown) to a predetermined thickness on the substrate 10 in advance, and then forming phosphorus (P), titanium ( It can also be formed by doping Ti), germanium (Ge), aluminum (Al), or the like. The optical waveguide structure 20 also has a refractive index material that can be used as a core, for example, deposited on the entire area of the substrate 10 to a predetermined thickness, and then boron (B) or fluorine (F) in a region corresponding to a clad layer portion (not shown). ) Etc. to selectively lower the refractive index. The optical waveguide structure 20 is a multi-component glass containing an arbitrary component having a thermal expansion coefficient of, for example, about 3.5 × 10 ⁻⁶ or less, and a region corresponding to the core (that is, the optical waveguide structure 20) is well known. It can also be formed by ion exchange by an ion exchange method and selectively changing the refractive index.

  FIG. 2 shows a state where the optical branching device shown in FIG. 1 is cut along a cutting line II.

  As shown in FIG. 2, an optical waveguide structure (core portion) 20 and dummy patterns 24A to 24H (FIG. 2 is a cross section taken along the cutting line II, so that only 24A to 24C can be seen). On top of this, a cladding layer 30 is deposited with a predetermined thickness, and an adhesive layer 25 is formed thereon with a predetermined thickness. A lid, that is, a cover glass layer 40, is fixed on the clad layer 30 by the adhesive layer 25 on the adhesive layer 25. Further, in the optical branching device 1 shown in FIGS. 1 and 2, the thickness of the substrate 10 is approximately 1 mm, the thickness of the core portion (optical waveguide structure) 20 and the length in the direction along the substrate 10 is approximately 6 μm (in the cross section). A rectangle having a side of approximately 6 μm), the thickness of the dummy patterns 24A to 24H is approximately 6 μm (the width varies depending on the position), the thickness of the cladding layer 30 is approximately 25 μm, the thickness of the adhesive layer 25 is approximately 25 μm, and the lid The thickness of 40 is approximately 1.5 mm. The thickness of the adhesive layer 25 is preferably set within a range of approximately 10 to 50 μm in consideration of the adhesive strength of the lid 40 and the deterioration of PDL.

  As is apparent from FIG. 2, the core portion 20 formed by patterning the optical waveguide structure (20) to a predetermined width (the length in the direction along the surface direction of the substrate 10) is formed on both sides (substrates). 10 except for 10 end portions), it is partitioned by dummy patterns 24A to 24H (as described above, only 24A to 24C are visible in FIG. 2). Further, the interval between the dummy patterns 24A to 24H and the core portion 20 will be described later with reference to FIG. 4, but is defined to be at least equal to or larger than the width (thickness) of the core portion 20. The Therefore, in FIG. 1, the dummy patterns 24E to 24H may be omitted between the core portions (20) indicated by the emission ends 23A to 23H, depending on the interval (number of branches) between the core portions. .

  FIGS. 3A to 3F are schematic views for explaining an example of a process (method) for manufacturing the optical branching device shown in FIGS. 1 and 2.

  First, as shown in FIG. 3A, for example, a glass flat plate mainly composed of silicon dioxide is prepared as the substrate 10. Subsequently, a material used as the optical waveguide structure 20 and the dummy patterns 24A to 24H having a higher refractive index than the refractive index of the substrate 10 on the substrate 10, such as silicon dioxide, is a CVD method (chemical vapor deposition method). Thus, a predetermined thickness is deposited. The thin layer of silicon oxide used for the optical waveguide structure 20 requires, for example, phosphorus (P), titanium (Ti), germanium (Ge), or aluminum (Al) to increase the refractive index. Depending on the doping.

  Next, as shown in FIG. 3B, a protective film 121 such as tungsten silicide (WSi) is deposited on the silicon oxide layer (20) to a predetermined thickness.

  Subsequently, a resist material (e.g., an etching resistant material such as a photo-curing resin) 122 is applied to the protective film 121 to a predetermined thickness, cured after a drying process (not shown), and then exposed to the core portion 20 by an exposure process (not shown). Patterns corresponding to the dummy patterns 24A to 24H are recorded (exposed). Hereinafter, the resist material is developed by a development process (not shown), and a resist pattern corresponding to the shape of the core portion 20 and the dummy patterns 24A to 24H (the protective film that has become an unetched pattern) as shown in FIG. ) 123 is formed.

  Next, as shown in FIG. 3D, the protective film 121 in the region to be etched is removed by, for example, an etching process. Therefore, the portion to be etched 124 to be etched in the subsequent process is exposed in the high refractive index layer (silicon dioxide) deposited to a predetermined thickness on the substrate 10 as the optical waveguide structure 20 first.

  Hereinafter, as shown in FIG. 3E, the etched portion 124 is removed by well-known dry etching, and the core 20 and the dummy patterns 24A to 24H (only 24B and 24C are visible in FIG. 3E). It is formed.

  Next, as shown in FIG. 3F, the clad layer 30 is used over the entire area of the substrate 10 including the core 20 and the dummy patterns 24A to 24H (only 24A to 24C are visible in FIG. 3F). A material such as silicon dioxide is deposited to a predetermined thickness. The clad layer 30 may be doped with, for example, boron (B) or fluorine (F) that can lower the refractive index.

  The core portion (optical waveguide structure 20), the dummy patterns 24A to 24H (optical waveguide structure 20), and the cladding layer 30 are not limited to the CVD method, and may be formed by, for example, a flame deposition method (FHD: Flame Hydrolysis Deposition method). The production method is not particularly limited to a specific production method.

  Subsequently, the adhesive layer 25 described above with reference to FIG. 2 is formed on the clad layer 30, and the cover (glass) layer, that is, the lid 40 is fixed on the adhesive layer 25. In addition, when the clad layer 30 swells in a region corresponding to the core 20 and the dummy patterns 24A to 24H (presents a convex portion), a smoothing (polishing) step (not shown) is performed before the adhesive layer 25 is formed. Accordingly, the surface irregularities, in particular, the convex portions may be flattened. Instead of the method of fixing the lid 40 on the clad layer 30 with the adhesive layer 25, the material of the clad layer 30 is previously equal to the material of the lid 40 or the thermal expansion coefficient is within a predetermined range. The lid 40 can also be fixed to the cladding layer 30 by using a material and disposing the lid 40 on the cladding layer 30 and then applying a predetermined pressure and heat to assimilate the lid 40 and the cladding layer 30.

  FIG. 4 shows a core portion (or a region corresponding to the core portion) when the optical waveguide structure shown in FIGS. 1 and 2 is etched to form a predetermined optical signal transmission path, that is, a core portion. It is the schematic explaining the factor by which the width | variety of an undesirably changes. In FIG. 4, the horizontal axis is [Process] for forming the core portion, and the distribution (3σ) of the variation in the width of the core portion (corresponding region) is obtained in each step. Further, in FIG. 4, each curve shows a distribution of the ratio of the dummy patterns 24 </ b> A to 24 </ b> H and the core portion 20 (see FIG. 1) to the area of the substrate 10 (see FIG. 1), that is, the occupation ratio and the width of the core portion ( 3σ), curve a is 90% occupancy, curve b is 70%, curve c is 60%, curve b is 30%, and curve e is 5%. Each is shown.

  Note that the occupation ratio of 90% corresponds to a state in which the areas of the dummy patterns 24A to 24H are set so that an interval substantially equal to the width of the core portion remains outside the core portion. An occupation ratio of 5% corresponds to a state where there is no dummy pattern.

  As is apparent from FIG. 4, it can be seen that the process in which the distribution (3σ) of the fluctuation in the width of the core portion becomes the largest is the etching process of the core portion. On the other hand, it is recognized that the variation (3σ) in the width of the core portion can be reduced to 0.15 μm or less by setting the occupation ratio to 70% or more. In particular, when the occupation ratio is 90% or more, the (3σ) can be reduced to 0.1 μm or less. When the occupation ratio is 5%, as indicated by the dividing line L in FIG. 1, the etching rate is greatly different between the light incident side and the light emitting side. It is reasonable to assume that the distribution of width variation (3σ) increases. Further, at the output ends 23A to 23H (see FIG. 1), the interval between the core portions is reduced according to the number of branches (channels), and therefore the interval between the core portions is the width of the core portion (along the surface of the substrate 10). If the length is less than twice the length of the direction (ie, the thickness of the core), the dummy pattern is not necessarily required.

  FIG. 5 is a schematic diagram showing a relationship between the pattern (total of core part and dummy pattern) occupancy and PDL when lid glass is bonded. In the PDL shown in FIG. 5, the size of the substrate 10 (see FIG. 1) is a square having a short side of 6 inches (about 125 mm), and the core portion (optical waveguide structure) 20 and dummy patterns 24A to 24H (see FIG. 5). 1)) and changing the total area.

  As is clear from FIG. 5, when the occupation ratio is 90% or more (the areas of the dummy patterns 24A to 24H are set outside the core portion so that an interval substantially equal to the width of the core portion remains), Was found to be reduced to 0.07 [dB].

  Further, by providing the dummy patterns 24A to 24H on the substrate 10 so that the occupation ratio becomes 70% or more (remaining a predetermined portion of the optical waveguide structure 20 to be unetched), the edge of the substrate 10 is etched. It has been confirmed that the degree to which the core portion provided in the portion is etched more than the core portion provided in the center of the substrate 10 or in the vicinity thereof is reduced.

  FIG. 6 is a schematic diagram for explaining the relationship between the occupation ratio of the core portion and the dummy pattern in the substrate and excess loss. In FIG. 6, curve a shows 90% occupancy, curve b shows 70%, curve f shows 50%, and curve e shows 5%.

As shown in FIG. 6, when the occupation ratio is small, the bent waveguide on the incident side is formed narrower than the other part due to the loading effect. For this reason, light leaks from the bent portion, and the loss increases on the long wavelength side. When the occupation ratio is increased, the bent waveguide has a uniform line width, so that light leakage is suppressed and a flat wavelength characteristic is obtained. In addition, although demonstrated previously using FIG. 4, the fluctuation | variation (3 (sigma)) of the width | variety of a core part can be 0.15 micrometer or less by making an occupation rate 70% or more. Further, by setting the occupation ratio to 90% or more, the variation (3σ) in the width of the core portion can be made 0.1 μm or less.

  As described above, according to the present invention, since the etching rate is substantially uniform over the entire area of the substrate, it is possible to prevent the core part width from fluctuating greatly at each branch destination (between channels). Even when the cover glass (lid) is adhered due to the presence of the dummy core, the optical branching unit having a low polarization dependence loss can be obtained.

  The present invention is not limited to the above-described embodiments, and various modifications or changes can be made without departing from the scope of the invention when it is implemented. Moreover, each embodiment may be implemented in combination as appropriate as possible, and in that case, the effect of the combination can be obtained. For example, in the above-described embodiments, an optical branching device that mainly branches an optical signal input to the input side has been described as an example. However, there is a plurality of input sides, and optical multiplexing in which the input optical signals are sequentially combined. And optical devices with optical waveguide structure formed on the substrate such as 1-input 2-output optical directional coupler that outputs optical signals input from one of two input ports from two output ports However, the same effect can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explaining an example of the optical branching device with which embodiment of this invention is applied. Schematic which shows the state which cut | disconnected the optical branching device shown in FIG. 1 along the II line. Schematic explaining an example of the process of manufacturing the optical branching device shown in FIG.1 and FIG.2. FIG. 3 is a schematic diagram for explaining a factor in which the width of a core portion (or a region corresponding to the core portion) changes undesirably in the optical branching device shown in FIGS. 1 and 2. Schematic explaining the relationship between occupancy [%] and PDL [dB]. It is the schematic explaining the relationship between an occupation rate [%] and excess loss [dB].

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical branching device, 10 ... Board | substrate, 20 ... Optical waveguide structure (core), 21 ... Light incident end, 22A-22G ... Optical branching part, 23A-23H ... Light emitting end, 24A-24H ... Dummy pattern, 25 ... Adhesive layer (adhesive), 30 ... cladding layer, 40 ... lid (cover layer).

Claims (13)

A light incident part where light is incident;
A light branching portion that branches the light incident on the light incident portion at a predetermined ratio;
A light emitting portion for guiding the light branched by the light branching portion to a predetermined position;
An adhesive layer formed in a predetermined thickness on the light incident part, the light branching part and the light emitting part;
A substrate for holding the light incident part, the light branching part and the light emitting part;
A cover member covering each of the light incident part, the light branching part and the light emitting part on the substrate via the adhesive layer;
A stress generated when the adhesive layer is cured is provided on the substrate independently of a region where the light incident portion, the light branching portion, and the light emitting portion are provided. , A stress leveling member that suppresses acting on any of the light branching portion and the light emitting portion, or the entire region,
An optical branching device comprising:   The stress equalizing member is a ratio of the total area of the areas of the light incident part, the light branching part and the light emitting part provided on the substrate to the area of the substrate and the area of the stress uniformizing member. 2. The optical branching device according to claim 1, wherein the optical branching device is defined to have an area in which a certain occupation ratio is larger than 70%.   The optical branching device according to claim 2, wherein the stress uniformizing member is defined to have an area where the occupation ratio is larger than 90%.   The optical branching device according to any one of claims 1 to 3, wherein the stress uniformizing member is formed of the same material as the light incident portion, the light branching portion, and the light emitting portion.   The optical branching device according to any one of claims 1 to 3, wherein the stress uniformizing member is formed in the same process as the light incident portion, the light branching portion, and the light emitting portion.   A light incident portion on which light is incident on a substrate, a light branching portion that branches light incident on the light incident portion at a predetermined ratio, and a light emission that guides the light branched by the light branching portion to a predetermined position And the light incident portion, light branching portion, and light emitting portion on the substrate are made of the same material as the light incident portion, light branching portion, and light emitting portion. And a stress leveling member provided on the substrate so that an occupation ratio indicating a ratio of a region excluding a region where the branching portion and the light emitting portion are provided is larger than 70%. .   The optical branching device according to claim 6, wherein the stress equalizing member is defined to have an area where the occupation ratio is larger than 90%.   The optical branching device according to claim 7, wherein the stress uniformizing member is formed in the same process as the light incident portion, the light branching portion, and the light emitting portion. On the substrate, a light transmission material layer having a higher refractive index than that of the substrate that can be used as an optical waveguide is deposited to a predetermined thickness
The optical transmission material layer has a first region used for transmitting an optical signal and a predetermined interval around the first region, and an etching rate for etching the first region is set to the entire area of the substrate. To define a second region to be generally constant,
Forming a non-etched pattern in each of the first region and the second region, and patterning the remaining region on the substrate by etching;
A material having a refractive index lower than that of the light transmission material layer is provided in a predetermined thickness over the entire region where the light transmission material layer and the substrate remaining after the patterning are exposed, and are different from the first and second regions. 3 regions are formed,
A cover member is bonded to the third region via an adhesive.
A method of manufacturing an optical branching device.   The area of the second region is set so that an occupation ratio obtained by dividing the total area of the first region and the second region by the area of the substrate is larger than 70%. Manufacturing method of optical branching device.   10. The method of manufacturing an optical branching device according to claim 9, wherein the area of the second region is an area that can reduce the influence of the stress generated when the cover layer is bonded to the first region. A light incident part where light is incident;
A light branching portion that branches the light incident on the light incident portion at a predetermined ratio;
A light emitting portion for guiding the light branched by the light branching portion to a predetermined position;
An adhesive layer formed in a predetermined thickness on the light incident part, the light branching part and the light emitting part;
A substrate for holding the light incident part, the light branching part and the light emitting part;
On the substrate, the light incident portion, the light branching portion, and the light emitting portion are provided independently of the region where the light incident portion, the light branching portion, and the light emitting portion are provided, and the light incident portion, the light branching portion, and the light emitting portion on the substrate are formed. Non-light that reduces the non-uniformity of the line width, which is the length of each of the light incident portion, the light branching portion, and the light emitting portion on the substrate along the surface direction of the substrate. A signal transmission area;
An optical branching device comprising: On the substrate, a light transmission material layer having a higher refractive index than that of the substrate that can be used as an optical waveguide is deposited to a predetermined thickness
The optical transmission material layer has a first region used for transmitting an optical signal and a predetermined interval around the first region, and an etching rate for etching the first region is set to the entire area of the substrate. To define a second region to be generally constant,
Forming a non-etched pattern in each of the first region and the second region, and patterning the remaining region on the substrate by etching;
A material having a lower refractive index than that of the light transmission material layer is provided in a predetermined thickness over the entire region where the light transmission material layer and the substrate remaining after the patterning are exposed, and are different from the first and second regions. 3 areas are formed
A method of manufacturing an optical branching device.

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